1. Field of the Invention
The present invention relates generally to impact-modified polyester/polycarbonate compositions which exhibit improved elongation at break in conjunction with excellent multiaxial toughness and low moulding shrinkage.
Provided that these compositions have been rendered flame-retardant, they exhibit flame retardant properties which are equal to or better than known compositions.
2. Description of Related Art
JP 06228425 describes blends of polycarbonate with two different polyesters, wherein both polyesters may contain other dicarboxylic acids in addition to terephthalic acid. The combination of ethylene glycol as alcohol component with small quantities of isophthalic acid in the acid component is, however, not described.
JP 08012864 describes impact-modified blends of polycarbonate and polyesters with oligophosphates as flame retardant. The polyesters may inter alia contain isophthalic acid, but exact proportions of the phthalic acid monomers in the compositions are not disclosed.
JP 05032800 discloses compositions prepared from 50-90% of a copolyester with 50-10% polycarbonate together with the films produced therefrom for foodstuffs packaging. The copolyester may contain various dicarboxylic acids and or diols, while impact modifier-containing compositions are not described.
EP 594021 describes impact-modified blends of polycarbonate and polyalkylene terephthalate with oligophosphates as flame retardant. The moulding compounds are distinguished by good stress cracking resistance, notch impact resistance and heat resistance combined with a good surface finish.
WO 2002008329 discloses flame resistant polycarbonate compositions with oligophosphate, which have a low IPP (isopropenylphenyl phosphate) content and, in addition to vinyl copolymers, may also contain polyalkylene terephthalates. The compositions exhibit improved mechanical properties, improved flame retardancy, improved heat resistance together with improved long-term stability.